Most women have hair on their breasts. How thick is the hair? If it is extremely thick, it may be a hormonal deficiency that has developed. If you are worried about this you can see your doctor. If you find the hair unattractive, you can always shave it.

I wouldn't suggest shaving hair on your chest. I have this problem and I wax it. It'll grow back fine and soft, not prickly like if you shave. And it'll take longer to grow back also.

You might want to see an endocrinologist to see if you might have PCOS. Which I have the good fortune to have. I can't remember how to spell what it's abbreviated for but a simple google search will tell you.

I'm a little late coming into this, but I have PCOS - Poly-cystic Ovarian Syndrome. It might be what you have. The excess of testosterone in your body can cause hair to grow thick and uneven on your face, neck, and yes, even on your chest - specifically around the nipples and on the sternum. Shaving only takes care of the problem for a couple days, and tweezing is painful and only lasts for four or five days anyway. Waxing isn't always the best route to follow if you're embarrassed by the hair growth, unless your waxer is someone you really, really trust. Electrolysis was recommended to me by my physician. Nevertheless, I agree with the idea of visiting an endocrinologist, just to be sure. Hair growth like that can be a symptom of PCOS and, if left untreated, can be very serious.